Flashcards
Thermal Physics
Flashcards do conjunto (31)
- 1Brownian Motion (evidence of moving particles)The bits of smoke are just big enough to be seen, but have little mass that they are jostles about by the air particles that hit them at random
- 2EvaporationWhen particles break away from the surface of a liquid and form vapours
- 3Boiling is..Occurs at only one temp.
Takes place at surface and in liquid
Rate of boiling depends on heat supply - 4Evaporation is...Occurs at all temp.
Only takes place at surface
Rate of evap depends on
1. temp
2. area and surface
3. state of air above surface - 5Boyls LawThe pressure of a fixed mass of gas is inversely proportional to its volume if the temp is kept constant
- 6Boyls law equationP1xV1=P2xV2
- 7Thermal expansionIdea that according to kinetic theory, the molecules of a solid and liquid are constantly vibrating. When they are heated, they move faster and further apart.
- 8Thermal/heat capacityAmount of energy needed to heat a kilo of substance by 1°C
- 9Specific heat capacityThe heat required to to produce a change of 1°C in a substance of 1 kg
- 10Equation for S.H.CQ
MxChange in T
Unit= J/kg°C
Q=Total heat - 11Thermal capacityMxC
Q
Change in temp
Unit=J/°C - 12Fire AlarmHeat from the fire makes the bimetallic strip bend and complete the electrical circuit , so ringing the alarm bill.
- 13Sensitivitythe ability of a thermometer to detect small changes in temperature
- 14Rangeis the range of temperatures which can be measured by the thermometer
- 15Linearitythe expansion of the liquid should be linear (uniform, the same) for all different temperatures measured.
- 16Liquid in glass thermometersThe bulb of thermometer contains liquid (e.g. mercury, alcohol) which expands when temperature rises and pushes a thread of liquid along the scale where temperature can be read
- 17Thermocouple1. Metals are joined to form a junction
2. a temp difference between the juctions cause a voltage
3. makes a current flow
4. great temp difference = greater current - 18condensationThis is the change of the physical state of matter from a gas into a liquid.
- 19SolidificationThis is the change of the physical state of matter from a liquid to a solid.
- 20Latent heatThe energy input, which is used to break down the structure of the material without change in temperature is called latent heat.
- 21Latent heat of fusionThe amount of energy needed to melt 1kg of substance without any change of temperature is called specific latent heat of fusion
- 22Latent heat of vaporisationThe amount of energy needed to change 1Kg of liquid into vapor without any change of temperature is the specific latent heat of vaporization of the liquid)
- 23Experiment for conduction1.Prepare a few rods made from different materials.
2.Use wax to attach small pins to their ends and then heat the other end of the rods.
3.The thermal energy will be transferred by conduction, from one end to the other
4. Eventually the wax will melt (due to the heat from the rod) and the pin falls off.
5.The best conducting rod will have its pin dropped off fastest because it transfers the thermal energy the fastest! - 24Conduction in solids1. Particles are fixed and cannot move
2. when heated, they gain kinetic and potential energy
3. they cannot move, so they vibrate instead
4. as the particles with more energy vibrate, they make others vibrate too
5. thermal energy is passed - 25Convection Currents1. Water becomes warmer, expands and density decreases, cools
2. denser water sinks and takes in place (displaces it) - 26Black surfacesDark or black surfaces tend to be good emitters and absorbers of heat
- 27Light surfacesWhite or light-coloured surfaces tend to be poor emitters and absorbers of heat.
- 28Experiment for emmitersPlace different materials of different colour under the sun, or close to a source heat radiation.
After a period of time, measure their temperature. The dark surfaces should be warmer because they are better absorbers of infra-red radiation. - 29S.H.CQ
MxT
Q is heat in joules - 30Latent heat of fusionQ
M
Unit- J/kg - 31Latent heat of vaporizationQ
M
Informações
- Descrição
- 11 Physics FlashCards sobre Thermal Physics, criado por mackiecaity em 20-12-2014.
- Criado por
- mackiecaity
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